Duplexer package

Abstract

A duplexer package comprises two surface acoustic wave filter chips having different band center frequencies and a phase matching circuit for matching the phases of the two SAW filter chips, the filter chips and the phase matching circuit being accommodated in one unit, wherein the phase matching circuit is formed in a layer providing a cavity for the filter chips, the layer defining the cavity being located above a face for mounting the surface acoustic wave filter chips. According to the present invention, the height of the duplexer package can be lowered.

What is claimed is: 
     
       1. A duplexer package comprising two surface acoustic wave filter chips having different center pass band frequencies and a phase matching circuit for matching the phases of the two surface acoustic wave filter chips, the filter chips and the phase matching circuit being accommodated in one unit, wherein the phase matching circuit is formed in a layer providing a cavity for the surface acoustic wave filter chips, the layer defining the cavity being located above a face for mounting the surface acoustic filter chips.   
     
     
       2. A duplexer package according to claim 1 wherein the layer providing the cavity includes a bonding terminal layer, a ground layer disposed under the bonding terminal layer, the ground layer including separate patterns for the individual surface acoustic wave filter chips, and a matching layer disposed under the ground layer, the phase matching circuit being formed on the matching layer. 
     
     
       3. A duplexer package according to claim 1 or 2 wherein a common ground layer is formed on the face for mounting the filter chips. 
     
     
       4. A duplexer package according to claim 1 or 2 wherein a common ground layer is formed under the face for mounting the filter chips with an insulating layer in between. 
     
     
       5. A duplexer package according to claim 3 wherein a common signal terminal is provided on the common ground layer and the phase matching circuit is formed between the common signal terminal and either one of the filter chips. 
     
     
       6. A duplexer package according to claim 4 wherein a common signal terminal is provided on the common ground layer and the phase matching circuit is formed between the common signal terminal and either one of the filter chips. 
     
     
       7. A duplexer package according to claim 1 or 2 wherein the phase matching circuit is made of a conductive material containing copper or silver as a principal component. 
     
     
       8. A duplexer package according to claim 1 or 2 wherein the phase matching circuit is formed of a strip-line to surround the surface acoustic wave filter chips. 
     
     
       9. A duplexer package according to claim 5 wherein the phase matching circuit is formed of a strip-line to surround the surface acoustic wave filter chips. 
     
     
       10. A duplexer package according to claim 6 wherein the phase matching circuit is formed of a strip-line to surround the surface acoustic wave filter chips. 
     
     
       11. A duplexer package according to claim 8 wherein the width of the strip-line varies at both ends thereof.